TORONTO - When Tina St. John was pregnant with her first child, the doctors told her they were surprised a woman five feet two inches tall who only weighed 80 pounds could conceive so easily.

St. John, 42, said the pregnancy was a constant tug-of-war between her battle with anorexia, a condition she had suffered from since her early teens, and a desire to be a healthy mother for her child.

"When you're chronically ill, your sense of reality around those issues is sort of warped," said St. John, now a mother of four who lives in Ottawa.

"It certainly was a concern, and in hindsight, it was a real threat," she said.

Experts say it's difficult to determine how common eating disorders such as anorexia and bulimia are among pregnant women because those types of statistics are rarely kept due to privacy concerns.

But according to a 2007-2009 Health Canada survey, 0.6 per cent of Canadian women between six and 79 years old reported suffering from at least one form of eating disorder.

In 2009-2010, there were 5,282 hospitalizations related to eating disorders, more than 90 per cent of the patients were women.

Some experts believe unrealistic body images in the media and a celebrity culture have led more women to try to stay thin during pregnancy so they can shed their weight immediately after childbirth.

"Before, pregnancy might have been seen (as) an opportunity to relax into one's body and to experience one's body as it naturally grows," said Merryl Bear, the director of the non-profit National Eating Disorder Information Centre in Toronto.

"But there are more challenges to a pregnant woman's self-perception that are exacerbated by the images and the stories of celebrities who get pregnant, have their babies, and throughout the process … just have their pre-pregnancy body with a bump,” she said.

Dr. Blake Woodside, head of Canada's largest eating disorders treatment program at Toronto General Hospital, said cases of eating disorders in pregnant women _ often referred to in the media as pregorexia _ used to be rare.

Our society, he said, has become "fatophobic and fat discriminatory," even when it relates to expectant mothers.

"When I started to work nearly 30 years ago in this field, a pregnant woman with anorexia would be treated like everybody else," he said. "At this point, they're immediately attached to a high risk pregnancy unit even if their condition isn't that severe.”

Official health guidelines suggest pregnant women should put on between 15 and 40 pounds during their nine-month term. The amount of weight gain varies with one's size prior to pregnancy and whether one is carrying a single fetus, twins or more.

Doctors say starving pregnant women are more likely to develop a number of health problems as are their babies.

The journal Canadian Family Physician warns that women who are anorexic during pregnancy have babies with lower Apgar scores and lower birth weights. The Apgar score assesses the general physical condition of a newborn. Other complications associated with pregorexia include depression, anaemia, hypertension, miscarriage and premature labour.

Fortunately, with a lot of support, St. John’s baby was born at a healthy nine pounds.

Since becoming a midwife three years ago, she has seen other women going through the same struggle of trying to maintain the perfect body shape with a baby growing inside.

People, she said, don't realize that the issues surrounding eating disorders are not just skin-deep.

"There's often other issues that go with it," she said. "When you're dealing with pregnancy and changing bodies and intimate body parts, it's also quite a challenge. It's not enough to just get the eating under control when you're being pulled out of yourself through growth and change."

Bear noted that there is much more awareness today about eating disorders, but said more must be done.

"An eating disorder is not about vanity,” Bear said. “That's really critical to express because there's so much stigmatization and with that stigma, comes discrimination against individuals with eating disorders.”

Bear said the expectant mothers suffering from an eating disorder feel a lot of anxiety and guilt.

“(They) are extremely concerned for the health of their babies," she said.

“It's an extremely difficult struggle for them because physical and emotional changes can actually trigger anxiety ... that they can only manage in disordered eating."